NOTES:
I factored out the common code between the JavaScript and CSS Highlighters and thus made two classes. I did not see any noticeable performance changes. But if we want, I still have to previous version which just has the two large js/css syntax highlight methods with the duplicated code.
I don't have time to whip up a css test file for a few days. Does anyone know of some CSS test files inside WebCore's tests that would help in testing edge cases?

I decided to implement the At Rule code and found out it was a lot worse then I had imagined. An at rule can either be
a single statement:
@import url(blah.css);
take a block of selectors:
@media print {
p { color: red; }
}
take not selectors but css properties and values:
@font-face {
font-size: 14pt;
}
So, I made a test case, implemented the parsing correctly, and compared with dashcode:
http://grab.by/7qc
I'll submit another patch for review because plenty of lines were added.